1. Field of the Invention
The present invention relates to a navigation apparatus, a navigation method, and a navigation program, and particularly, to a navigation apparatus, a navigation method, and a navigation program having a stored history of route elements passed in the past.
2. Description of the Related Art
A navigation apparatus is a system for guiding a user through a route from a departure place to a destination to support a travel of the user. The navigation apparatus searches for a route from a current position (departure place) to a destination when the user sets the destination. The navigation apparatus stores, as route elements, information of roads divided at intersections on a map and information of the intersections. In the route search, the navigation apparatus combines the route elements to search for, as a route, a combination with a minimum route cost including distance, average travel time, road width, the number of left and right turns, and the like (however, weights are added according to priorities). A display apparatus of the navigation apparatus displays the searched route, and the route guide is presented according to the route and the current position.
The user may not always need the route guide from the navigation apparatus. For example, the user does not need excessive information from the route guide when the user knows the route leading to the destination well.
A conventional navigation apparatus that selects a simple guide mode and a detailed guide mode in the route guide is known (for example, see Japanese Patent Laid-Open No. 2007-10572). In the conventional navigation apparatus, the simple guide mode for simple route guide takes place when guiding a route familiar to the user and the detailed guide mode for detailed route guide takes place when guiding a route that is not familiar to the user. The navigation apparatus needs to know whether or not the user is familiar with the route elements to be presented for the route guide in order to appropriately change the guide level in the route guide.
If more than one combination of the route elements exist from a departure place to a destination in the route search, the conventional navigation apparatus searches for a route so as to pass through more route elements familiar to the user than other routes. Also in this regard, the navigation apparatus needs to know whether or not the user is familiar with the route elements in the searched route.
The conventional navigation apparatus considers a route element through which the user has passed for more than a predetermined number of times in the past to be a regular route element, or a route element familiar to the user.
However, since determination as to whether the user is familiar with the route element is made based only on the number of passages, a route element that the user scarcely passes now while the user was used to frequently pass in a certain period in the past and thus may not be familiar to the user (who has forgotten) may be recognized as a route element familiar to the user.
The present invention has been made to solve the problem, and an object of the present invention is to improve accuracy of determination as to whether route elements stored as a history are familiar to the user, with a navigation apparatus that stores the history of the route elements passed in the past.